Are you aware that building a 'L' shape extension will need planning permission first, this will set you back another 3-4 months. Plus Building Regs would need reapplying for. Also, from my experience conservatories only need building regs approval if they are over 30sqm; which means most conservatories are shoddy built and the foundations are unlikely to be suitable for the transformation into a proper extension. Also, the floor is unlikely to have been insulated - sorry but conservatories can be a hornets nest of problems. My advice is yes you should have a door off the hallway into the new room, cost of that should be minimal as you are only looking at using a couple of standard concrete lintels which are cheap as chips! Although I would have put the shower room at the front as the current layout means friends and visitors end up going through your kitchen to use the convenience. It has the advantage the new reception room as a rear garden outlook. Hope that helps

Brilliant things to consider Minnie thank you. Only 4 of us in the house, and we do have a seperate dining room. I only want casual bar stool seating for the kitchen but am struggling with where else to place 4 bar stool. Haven't got the width of room to have them all down the side of island facing the wall of units, plus I really like the sleek look of an island and didn't want to interupt that streamlined look by having seating around one end in an L shape. Can't thing of any other option unless someone can thing of something to consider I'd be very grateful. I had my heart set on a mirror splash back but got put off as people said I would have water marks on it all the time from the sink.....is that everyone's experience of a mirror splashback or might I have made a hasty judgement? I was thinking of a washed light grey oak type flooring or a warm oak flooring but was worried if I went for oak ( this would be my colour preference) that it wouldn't work as I will have nothing else oak in the room. It's a south facing room, sun all day and evening so was thinking of a off white light grey tone on the walls and lots of chrome......again struggling to know how to incorporate that and what to put with it colour/ accent/ decor wise to make it feel comfy and not clinical. I'd love dark coloured glass slider but all windows in house are white so I had discounted it. Minnie thanks a million for taking the time on your bumpy train journey to post, I cannot tell you how grateful I am to have your input

Sounds like you will need to apply for planning permission because of the roof heights from ground level. Best thing to do though is to call and check with your planning department - if you can speak with someone! Ask to speak to the duty officer. Alternatively, if a quick call isn't possible you can go the paid for pre-app route, although more effective once you've got some sketch plans done.. I've found some variance in interpretation on what would be considered ground level from one city to another, so yours might take a particular view that may or may not be helpful to you! I think the permitted height you mention is to gutter level off the ground level - so the ridge / abutment can be higher than that. (This is all a bit off the top of my head - as in I'm not reading directly from any planning policy or guidance here but it sounds like you're reasonably familiar with the documents anyway). For the drain that runs under the patio you need to check with your local water board or building control department for what you need to do if it's their responsibility. Again different water boards have extremely different requirements and guidance. Some, like United Utility tend to let the building control department deal with it and have reasonable rules around altering manholes etc. Other water boards like South West Water insist that you apply directly them and have really strict and onerous requirements and allow very minimal to no alterations to things like manholes. If you do have a shared drain then you will need to have permission to build over it and you will probably need to make sure it can be accessed via a rodding eye or manhole - all dependent on the specific requirements of the water board in your area and the specific layout of your drain and property. You may also need to have a structural report to show that no additional load is being put on the drain that might cause cracking or other problems, and possibly other requirements... It can be a bit of a pain to be honest depending on the specifics, but if it's important enough to do it then there are usually (though not in every case) ways to achieve a build over. For internal changes in level compared to external - this is up to you and how you plan to use the space, how mobile you are and comfortable with steps - for example if you have young kids, or plan to have, then some steps in the middle of your family room might seem a bit dangerous. A good designer can incorporate steps within a room well if you prefer that, or you can do them externally within a raised patio, but you will need to include for that patio within your planning application if it's over (if I remember right) 50cm off ground level. In relation to the neighbours you may need to prove that they will not have their enjoyment of their property reduced or limited by your proposal. In some areas there are strict house extension guidelines that you have to follow - for example Farnham and Trafford. The main things are privacy and overshadowing. Your architect should be able to create diagrams to help support any design and show the planners that this has been taken into consideration and won't have a majorly negative effect on the neighbours. If you'd like my free checklist to help you with your fundamental decisions making you can get that here: https://bit.ly/2P1quQ6 Hope this helps, Jane, i-architect.co.uk

Jonathan, funny you say this as my first sketches were for sink where hob is and a floor to ceiling window looking out to garden! for the exact reason that sink there is 'traditional' so I totally get what your saying. the reason we changed from that plan was at that point the hob was on the island, when we changed that idea I then wasn't sure about both hob and sink along the run of cabinets, both facing a wall, wondered if we would feel we'd made the kitchen boring and antisocial as would always be facing the away from the room? and lack of pantry we were quite pleased with the extra cupboards it brings. the understair we will be taken out so the garage conversion bathroom will be the only we on ground floor, the bath is a must I'm afraid as we are really missing it and don't want to cramp the upstairs bathroom by putting one in as that's the high use shower. I've always assumed air con would be expensive and ugly? we are going for electric velux sky lights so will be easy to open. thanks for your input, always so helpful to get other perspectives.